The traditional approach for cooling turbine blades and nozzles is to extract high pressure cooling air from a source, for example, by extracting air from the intermediate and last stages of a turbine compressor. In modern turbine designs, it has been recognized that the temperature of the hot gas flowing past the turbine components could be higher than the melting temperature of the metal. It is, therefore, necessary to establish a cooling scheme to protect hot gas path components during operation. In combined cycle plants, steam may be the preferred cooling medium. While diverted coolant air, for example, from the compressor, does not receive energy directly from the combustor of the turbine and represents a parasitic loss to turbine output degrading overall performance, it has been found useful to combine steam cooling and air cooling in a nozzle stage of the turbine after the first turbine stage. Impingement air cooling of stator vanes is, per se, known. However, impingement air cooling degrades as cross-flow increases. It is, therefore, desirable to minimize the magnitude of the cooling air flow required for trailing edge cooling.